Role of oxygen partial pressure on structure and properties of sputtered transparent conducting films of La-doped BaSnO3

Abstract

Single crystal film of La doped BaSnO3 (LBSO) has been reported with excellent conductivity and transparency but in order to improve its applicability, it is important to grow polycrystalline LBSO films on inexpensive substrate. A series of polycrystalline LBSO thin films of ~570 nm in thickness are grown on quartz substrate by radio frequency magnetron sputtering at different oxygen pressures varying from 0 to 0.13 Pa. Both carrier concentration and mobility of the films seem to be decreasing with increasing oxygen pressure. The estimated values of mobility, carrier concentration and conductivity are 5.21 cm2/V s, 9.1 × 1019 cm−3 and 2.8 × 102 Ω−1 cm−1, respectively, with optical transmittance of 68% for the film deposited at lowest oxygen partial pressure (0.01 Pa). The optical transmittance of the films improves significantly upto 82% with increasing oxygen pressure to 0.13 Pa. The suitable condition for deposited films is observed at 0.05 Pa in terms of transmittance (~80%) and conductivity (0.67 × 102 Ω−1 cm−1) which is almost 8 times superior to previously reported conductivity (9 Ω−1 cm−1) for polycrystalline LBSO films and comparable to the conductivity (102 Ω−1 cm−1) of the hetero-structured LBSO thin films. Overall, understanding of changes in microstructure, electrical and optical properties of thin film by varying oxygen pressure have been reported effectively. The LBSO films prepared in the current work could be further utilized in TCO applications.